Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

The Food and Drug Administration says people shouldn’t buy the drugs, and will warn the companies involved to stop selling the products as formulated.

It’s the second warning in a month about male enhancement products containing the same chemical compounds found in prescription drugs such as Viagra and Cialis. The drugs can cause serious problems in men with heart disease and can interact with other prescription drugs.

The products carry suggestive names: “Ninja Mojo”, “Love Rider” and “Affirm XL”. “Consumers should stop using this product immediately and throw it away. Consumers who have experienced any negative side effects should consult a health care professional as soon as possible,” the FDA says in its warning notice.

Affirm XL’s website was still available soon after the warning was issued, and it lists a batch of natural ingredients such as gingko and royal jelly. It doesn’t mention what FDA testers found.

“FDA laboratory analysis confirmed that “AFFIRM XL” contains the undeclared ingredient sulfoaildenafil,” the agency said in a statement.

“Sulfoaildenafil is structurally similar to sildenafil, the active ingredient in Viagra, an FDA-approved prescription drug for erectile dysfunction (ED). This undeclared ingredient may interact with nitrates, which are found in some prescription drugs, such as nitroglycerin. This interaction may lower blood pressure to dangerous levels. Men with diabetes, high blood pressure, high cholesterol, or heart disease often take prescription drugs that contain nitrates."

Affirm XL’s site links to a YouTube video featuring rapper Warren G, dressed in a silky red bathrobe and surrounded by admiring, scantily dressed women. The “commercial is supposed to be funny”, Warren G is quoted as saying in a statement posted on his website. It “is not something that dictates who I am."

An FDA spokeswoman says the companies that make these products usually comply when asked by the FDA to stop marketing them as is. The agency can take further action, including seizure, if needed, she said.

“This notification is to inform the public of a growing trend of dietary supplements or conventional foods with hidden drugs and chemicals,” FDA said.

“These products are typically promoted for sexual enhancement, weight loss, and body building, and are often represented as being ‘all natural.’ FDA is unable to test and identify all products marketed as dietary supplements on the market that have potentially harmful hidden ingredients.”

The FDA can regulate products categorized as drugs, but Congress has passed legislation exempting supplements such as vitamins from any FDA regulation.